GPT-5.5 Instant vs GPT-5.5 Pro
GPT-5.5 Instant Verdict
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 59.2.
- GPT-5.5 Instant is stronger in agents & tools, coding, composite, human preference, instruction following, knowledge, long context, multimodal.
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- GPT-5.5 Instant is 6.0× cheaper ($11.25 vs $67.50 per 1M blended).
- GPT-5.5 Instant streams 32.7× faster (131 vs 4 tokens per second).
| Metric | GPT-5.5 Instant | GPT-5.5 Pro (xhigh) |
|---|---|---|
| BenchLeader Index | 59.2 | 67.1 |
| Agents & tools score | 49.9 | – |
| Coding score | 61.0 | – |
| Composite score | 62.9 | – |
| Human preference score | 67.4 | – |
| Instruction following score | 70.0 | – |
| Knowledge score | 69.5 | – |
| Long context score | 61.3 | – |
| Maths score | 50.1 | 74.5 |
| Multimodal score | 59.3 | – |
| Reasoning score | 56.3 | 80.1 |
| Blended price $/M | $11.25 | $67.50 |
| Output speed | 131 tok/s | 4 tok/s |
| Time to first answer | 16.3 s | 3.5 s |
| Context window | 400k | 1.1M |
| GPQA Diamond | 82.5% | – |
| FrontierMath Tiers 1–3 | 26.3% | 87.7% |
| FrontierMath Tier 4 | 2.4% | 78.0% |
| OTIS Mock AIME | 68.1% | – |
| SciCode | 48.6% | – |
| Epoch Capabilities Index | 142.5 | – |
| LMArena Text | 1474 | – |
| LMArena Hard Prompts | 1491 | – |
| LMArena Coding | 1514 | – |
| LMArena Vision | 1251 | – |
| AA Intelligence Index | 26.8 | – |
| IFBench | 71.5% | – |
| AA-LCR | 70.0% | – |
| AA-Omniscience | 11.2 | – |
| Terminal-Bench Hard | 42.4% | – |
| GPQA Diamond (AA) | 84.7% | – |
| Humanity's Last Exam (AA) | 21.6% | – |
| SciCode (AA) | 52.5% | – |
| τ²-Bench Telecom (AA) | 49.4% | – |
| ARC-AGI-1 | – | 95.0% |
| ARC-AGI-2 | – | 84.2% |
| CritPt | 2.6% | 30.6% |
| GDPval (AA) | 8.1% | – |
| τ²-Bench Banking (AA) | 11.8% | – |
| LMArena Maths | 1463 | – |
| LMArena Creative Writing | 1456 | – |
| LMArena Instruction Following | 1456 | – |
| LMArena Multi-turn | 1483 | – |
| LMArena Longer Queries | 1475 | – |
| LMArena Document | 1460 | – |
| Chess Puzzles | 12.0% | – |
| LMCA | – | 53.9% |
| DTBench | – | 96.0% |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Instant vs GPT-5.5 Pro: questions
- Is GPT-5.5 Instant better than GPT-5.5 Pro?
- GPT-5.5 Pro (xhigh) leads on quality: 67.1 vs 59.2. The BenchLeader Index combines every independent quality benchmark; GPT-5.5 Pro (xhigh) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Which is cheaper, GPT-5.5 Instant or GPT-5.5 Pro?
- GPT-5.5 Instant is cheaper: $11.25 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Instant or GPT-5.5 Pro?
- GPT-5.5 Instant streams faster: 131 against 4 output tokens per second.
- Which has the larger context window?
- GPT-5.5 Pro accepts more context: 1.1M against 400k tokens.